Propeller



Oct; 12, 1 954 c. ANDERSEN PROPELLER Filed March 10 1950 INVENTOR. C/mEL E5 AA/az/esE v m I ,4 TTO/P/VEX Patented Oct. 12, 1954 ggg sgggUNITED STATES PATENT OFFICE PROPELLER Charles Andersen, New York, N. Y.Application March 10, 1950, Serial No. 148,987 1 Claim. (01. 170-165) 1My invention relates to propellers for impartdescribed, when rotationoccurs as indicated at ll, ing motion to boats or vessels in a fluidmedium. the fluid engaged by the inboard blades is More particularly myinvention pertains to propassed without substantial turbulence into thebite pellers especially adapted for imparting motion to of the blades ofthe outboard propeller 5, where, marine craft. Generally my inventiveidea is ap- 5 due to the form of the blade profile the initial plicableto propellers whether employed for imthrust of the outboard propeller isnot only mainparting motion to a craft or for imparting motained butsubstantially augmented and accelertion to a fluid in which thepropeller is operating. ated. In the disclosure but two propellers areAmong the objects of my invention is to proshown and discussed but itshould be understood vide a propeller that may be economically opthatthe novel principle herein described may be erated at high efliciency.It is also an object to applied to more than two tandem propellerssuitprovide a substantially non-cavitating propeller ably spaced apartand angularly set relative to capable of exerting a powerful thrust.Further each other. While the full benefit of the inobjects and theunique advantages of my invenvention is best realized when thepropellers are tion will be brought out as the following specidriving intheir intended direction the system fication is read in conjunction withthe drawings may be operated in the reverse direction. In a forming apart of this application, in which: marine application, for example whengoing Figure 1 is a front elevation of a propeller emahead, water forced01f the driving faces of the bodying my invention. blades lb of theinboard propeller 6 is driven Figure 2 is a side elevation of Fig. 1,partly in to the back side of the blades l5 of the outboard section, online 2-2 of Fig. 1. propeller 5, thereby increasing the overall thrustFigure 3 is a series of profile sections of a blade of the unit andincreasing the driving speed or of a propeller made according to myinvention propulsion travel rate. In Fig. 2, the sleeve 1 taken on thelines A-A, B-B, C-C and D-D. carrying the propeller blades 5 and 6, isshown Figure 4 is a series of profile sections of an- 2 as having atapered bore it fitted to a similarly other blade of my propeller takenon the lines tapered portion 9 of a shaft 10, carried in a suit- E-E,F-F, G-G and HH. able bearing II, the sleeve 1 being secured uponReferring to Fig. 1 of the drawing 5 are the the tapered portion of theshaft by means of a nut blades of the outboard or first propeller, and6, 5 l2 screwed onto the threaded portion l3 of the are the blades ofthe inboard or second propeller. 3O shaft I0 and covered by the can M.As may be It will be noted that both propellers are carried noted in theviews, the leading edges of blades 5, 5, by a single sleeve 1 and thatone set of blades 8, 6 etc., are indicated at l 5, I 5, while theleading is set at an angle of about degrees in advance edges of theother blades 6, 6, etc., are noted it, of the blades 5, 5 of the other.Obviously in place [6, inasmuch as the normal rotation of the proof thesingle sleeve 1, each propeller, complete with pellers occurs in thedirection indicated in Figi s wn sleeve, y be stru t d d pend ntly ure 1by arrow l1. Having described and il1usand thereby re ly Set at anppropriate relatrated a preferred embodiment of my invention tive angle.A purpose of the two propellers, set h t I 1m as new i one behind theother and having their blades In a propeller system, a first or outboardprosuitably profiled, is to develope the utmost efpeller mounted upon adrive shaft, said first profective power from the motive force impartedto peller consisting of three identical blades, said it and to reduce toa minimum the amount of slip blad being equi-angularly spaced from eachand drag. As indicated by the series of p il s other, each of saidblades having concave driving (Fig. 3) the blades of the outboardpropeller 5 surfaces and convexly curved back. surfaces, a may be formedin the usual manner, the outersursecond or inboard propeller mountedupon the f e be li t y convex and the under surface same drive shaft assaid first propeller, said first being dished or concave so that inoperating relaand second propellers being spaced apart and potive to afluid medium a screw-like path is desitioned in tandem, the said secondpropeller con- Scri dhe oa propeller owever, which sisting of threidentical blades, said last meniS Set w y from the other p p r a p edtioned blades of the second propeller being equitermined distance, asindicated in Fig. 4 prefangularly spaced from each other, each of saiderably is formed to provide a different set of blade latter bladeshaving fiat driving surfaces and lint profiles 1. e.: the outer faces ofsame being subback surfaces, said blades being tapered from stantiallyflat and tapered in cross section, the their front edge to their rearedge on said back entering edge being relatively thin. By the meanssurfaces, said second propeller being spaced angu- I! 12 larly behinsaid first propeller whereby to pro- Number vide a space to allow waterto go through, both 1,767,786 of said propellers being of substantiallythe same 1,954,309 diameter. 2,128,780

5 References Cited in the file of this patent UNITED STATES PATENTS g gNumber Name Date 1,021,822 Broussouse Apr. 2, 1912 10 Name DateEngstrand June 24, 1930 Cutolo Apr. 10, 1934 Lefi Aug. 30, 1938 FOREIGNPATENTS Ceuntry Date Great Britain 1912

